1 files changed, 69 insertions, 0 deletions
diff --git a/tests/NonlinearBlendingTest.cpp b/tests/NonlinearBlendingTest.cpp
new file mode 100644
index 0000000000..0ea7d47dab
--- /dev/null
+++ b/tests/NonlinearBlendingTest.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "../third_party/skcms/skcms.h"
+#include "SkColorSpace.h"
+#include "SkColorSpaceXformSteps.h"
+#include "Test.h"
+
+DEF_TEST(SkColorSpaceXformSteps_vs_skcms, r) {
+    auto srgb = SkColorSpace::MakeSRGB();
+    auto dp3  = SkColorSpace::MakeRGB(SkColorSpace::kSRGB_RenderTargetGamma,
+                                      SkColorSpace::kDCIP3_D65_Gamut);
+
+    skcms_ICCProfile srgb_profile;
+    srgb->toProfile(&srgb_profile);
+    skcms_ICCProfile dp3_profile;
+    dp3->toProfile(&dp3_profile);
+
+    // These colors provide a good spread of interesting test cases.
+    SkColor colors[] = {
+        0xffff0000, 0x7fff0000, 0x7f7f0000,
+        0xff00ff00, 0x7f00ff00, 0x7f007f00,
+    };
+
+    for (auto color : colors) {
+        auto bgra = skcms_PixelFormat_BGRA_8888,
+              f32 = skcms_PixelFormat_RGBA_ffff;
+        auto unpremul = skcms_AlphaFormat_Unpremul,
+               premul = skcms_AlphaFormat_PremulAsEncoded;
+
+        float via_skcms[4];
+        skcms_Transform(&color,     bgra, unpremul, &srgb_profile,
+                        &via_skcms,  f32,   premul,  &dp3_profile,
+                        1);
+
+        SkColorSpaceXformSteps steps(srgb.get(), kUnpremul_SkAlphaType, dp3.get());
+        float via_steps[4] = {
+            SkColorGetR(color) * (1 / 255.0f),
+            SkColorGetG(color) * (1 / 255.0f),
+            SkColorGetB(color) * (1 / 255.0f),
+            SkColorGetA(color) * (1 / 255.0f),
+        };
+        steps.apply(via_steps);
+
+        REPORTER_ASSERT(r, fabsf(via_skcms[0] - via_steps[0]) <= 0.005f);
+        REPORTER_ASSERT(r, fabsf(via_skcms[1] - via_steps[1]) <= 0.005f);
+        REPORTER_ASSERT(r, fabsf(via_skcms[2] - via_steps[2]) <= 0.005f);
+        REPORTER_ASSERT(r, fabsf(via_skcms[3] - via_steps[3]) <= 0.0f);
+
+        // Now go back using the other method's inverse transform
+        float steps_to_skcms[4];
+        skcms_Transform(via_steps,      f32, premul, &dp3_profile,
+                        steps_to_skcms, f32, premul, &srgb_profile,
+                        1);
+
+        float skcms_to_steps[4] = { via_skcms[0], via_skcms[1], via_skcms[2], via_skcms[3] };
+        SkColorSpaceXformSteps inv_steps(dp3.get(), kPremul_SkAlphaType, srgb.get());
+        inv_steps.apply(skcms_to_steps);
+
+        REPORTER_ASSERT(r, fabsf(skcms_to_steps[0] - steps_to_skcms[0]) <= 0.005f);
+        REPORTER_ASSERT(r, fabsf(skcms_to_steps[1] - steps_to_skcms[1]) <= 0.005f);
+        REPORTER_ASSERT(r, fabsf(skcms_to_steps[2] - steps_to_skcms[2]) <= 0.005f);
+        REPORTER_ASSERT(r, fabsf(skcms_to_steps[3] - steps_to_skcms[3]) <= 0.0f);
+    }
+}